In his famous "Mikroskopische Untersuchungen," Schwann speaks of
_Torula_ as a "cell;" and, in a remarkable note to the passage in
which he refers to the yeast plant, Schwann says:--

"I have been unable to avoid mentioning fermentation, because
it is the most fully and exactly known operation of cells,
and represents, in the simplest fashion, the process which is
repeated by every cell of the living body."

In other words, Schwann conceives that every cell of the living body
exerts an influence on the matter which surrounds and permeates it,
analogous to that which a _Torula_ exerts on the saccharine solution
by which it is bathed. A wonderfully suggestive thought, opening up
views of the nature of the chemical processes of the living body,
which have hardly yet received all the development of which they are
capable.

Kant defined the special peculiarity of the living body to be that the
parts exist for the sake of the whole and the whole for the sake of
the parts. But when Turpin and Schwann resolved the living body into
an aggregation of quasi-independent cells, each, like a _Torula_,
leading its own life and having its own laws of growth and
development, the aggregation being dominated and kept working towards
a definite end only by a certain harmony among these units, or by the
superaddition of a controlling apparatus, such as a nervous system,
this conception ceased to be tenable. The cell lives for its own sake,
as well as for the sake of the whole organism; and the cells, which
float in the blood, live at its expense, and profoundly modify it, are
almost as much independent organisms as the _Torulae_ which float in